Mighty Gem
I'm probably over-sensitive because I know just how keen the CAA Enforcement & Investigation Branch is to prosecute pilots when they think they have sufficient evidence to get a conviction.
Droopy says "..... to whom else do they (the local police) turn when Mr Angry is complaining about a landing upsetting his day?" Fair point. So, supposing (just for example) that, as a result of a discussion on this thread, you concluded that a pilot landing at a particular private site in your area was breaking a provision in Rule 5, you might feel (because of your job) that you'd have to say so if asked by the local police. That might lead to a prosecution by the CAA.
Of course, the police might ask the CAA anyway, but at least in those circumstances we wouldn't have done anything which helped get a pilot into trouble.
The root of the problem lies in the prosecution culture at the CAA which inevitably creates an adversarial 'us and them' divide.
I believe very strongly that it would do far more to enhance flight safety if, instead of their 'investigate and prosecute' approach, the CAA adopted an 'investigate and educate' approach in which all those involved could speak freely and, where appropriate, learn. That can't happen when the people whose actions are being investigated know they are at risk of being prosecuted if they admit doing anything which amounts to an offence.
MBJ
The final paragraph of your post is just plain wrong. That case was at the end of 2000 and the CAA has prosecuted many people since.
(It's always dangerous to make a judgment based on newspaper reports. The pilot was accused of endangering. The jury heard the evidence, including evidence from people who saw the helicopter land and depart, and didn't think he endangered anybody so found him not guilty. )
Tudor Owen